There has been used a prober as a wafer inspection apparatus to perform an electrical characteristic test on each of multiple semiconductor devices formed on a semiconductor wafer (hereinafter, simply referred to as “wafer”). The prober includes a probe card facing the wafer, and the probe card includes multiple contact probes as a multiple number of column-shaped contact terminals (see, for example, Patent Document 1). In this prober, a test signal is outputted to a semiconductor device connected to an electrode pad or a solder bump through each of the contact probes of the probe card, so that a conducting state of an electrical circuit of the semiconductor devices can be inspected.
A test signal is sent to each of the contact probes of the probe card from a test head having a main board as a test circuit. Recently, in order to improve wafer test efficiency, there has been developed a wafer inspection apparatus which includes multiple test heads each having a probe card and inspects a semiconductor device of a wafer with a single test head while the wafer is transferred to another test head. In this wafer inspection apparatus, from the viewpoint of reduction in footprint, cells each accommodating multiple test heads are stacked at multiple levels.
Since a main board of each test head is a kind of consumables, the main board needs to be regularly replaced. In order to replace the main board, the test head needs to be unloaded from the wafer inspection apparatus to above a maintenance carriage.
Patent Document 1: Japanese Patent Laid-open Publication No. 2012-063227
However, the test head has a weight of about 70 kgf and is supported by a slide rail. Thus, it is difficult to move the test head in other directions than in an unloading direction. Therefore, it is necessary to correctly adjust a position of the maintenance carriage to a position of the test head. However, since the maintenance carriage includes a lift device or the like and has a high weight, it is difficult to fine control the position thereof. As a result, it is difficult to unload the test head.